Wireless local area networks (WLANs) are becoming a common way to network or interconnect devices with wireless capabilities in a residential or business setting. However, one disadvantage with using a WLAN is the possibility that sensitive or private information may be accessed, modified, or intercepted by an unauthorized party. These problems may be mitigated or reduced by setting up a secure WLAN that uses a cryptographic system to encrypt information exchanged between devices interconnected in a WLAN. In this secure WLAN, only those authorized have the ability to decrypt encrypted information. Thus, even if the encrypted information is intercepted by an unauthorized party, the encrypted information is not intelligible without the ability to decrypt the information. In this manner, an insecure WLAN may act functionally like a private and secure network.
One example, of a cryptographic system is a public key cryptographic system. The basic components of a public key cryptographic system include a cryptographic algorithm and two numerical codes called keys, one of which is referred to as a public key and the other a private key. For encryption, information encrypted with the public key (or public encryption key) can only be decrypted with the private key (or private decryption key). For example, if a message is encrypted with the public key, only the holder of the associated private key can recover the original message. Even the originator of the message, absent the private key associated with the public key, cannot decrypt the message.
Another example of a cryptographic system for a secure WLAN is a system designed for WLAN networks. One such system is described in the Institute for Electrical and Electronic Engineers (IEEE) 802.11i standard for medium access control (MAC) security enhancements. See IEEE 802.11i-2004: IEEE Standard for Information technology—Telecommunications and information exchange between systems—Local and metropolitan area networks—Specific requirements Part 11: WLAN MAC and Physical Layer (PHY) Specifications, Amendment 6: MAC Security Enhancements, published July 2004, and/or later versions of the standard (the “802.11i standard”). In this cryptographic system, following the authentication of a device, a controlling agent of a WLAN may exchange a pairwise master key (PMK) with each authenticated device. The PMK, for example, is then used for secure 802.11i operations or communications on the WLAN.